Using a horizontal force of 200, N , we intend to move a wooden cabinet across a floor at a constant

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8. FORCE AND LAWS OF MOTION

easy

Using a horizontal force of $200\, N$, we intend to move a wooden cabinet across a floor at a constant velocity. What is the friction force(in $N$) that will be exerted on the cabinet?

$100$

$400$

$200$

$300$

Solution

A force of $200\, N$ is applied in the forward direction. Thus, from Newton's third law of motion, an equal amount of force will act in the opposite direction. This opposite force is the fictional force exerted on the cabinet. Hence, a frictional force of $200\, N$ is exerted on the cabinet.

Standard 9

Science

An object of mass $1 \,kg$ travelling in a straight line with a velocity of $10\, m\, s^{-1}$ collides with, and sticks to, a stationary wooden block of mass $5\, kg$. Then they both move off together in the same straight line. Calculate the total momentum just before the impact and just after the impact. Also, calculate the velocity of the combined object.

hard

Two objects, each of mass $1.5\, kg$, are moving in the same straight line but in opposite directions. The velocity of each object is $2.5\, m \,s^{-1}$ before the collision during which they stick together. What will be the velocity(in $m/s$) of the combined object after collision?

hard

A batsman hits a cricket ball which then rolls on a level ground. After covering a short distance, the ball comes to rest. The ball slows to a stop because

medium

What is the momentum of an object of mass $m$, moving with a velocity $v$ ?